Intramolecular Electrophilic Cyclization Research Articles

ChemInform Abstract: Hg/Pt‐Catalyzed Conversion of Bromo Alkynamines/Alkynols to Saturated and Unsaturated γ‐Butyrolactams/Lactones via Intramolecular Electrophilic Cyclization.

AbstractDepending on the tether between the substrates′ bromoalkyne and the hydroxy or tosylamino group, respectively, the selective formation of saturated or unsaturated lactams, unsaturated lactones, oxazinones or α‐bromoketones is observed.

Assembly of 3-(trifluoromethyl)thiochromenes via a regioselective trifluoromethylthioarylation of (3-arylprop-2-ynyl)oxybenzenes with trifluoromethanesulfanylamide

An intramolecular electrophilic cyclization of (3-arylprop-2-ynyl)oxybenzenes with trifluoromethanesulfanylamide is reported, which affords 3-(trifluoromethyl)thiochromenes in good yields with high regioselectivity. The reaction works efficiently in the presence of 2.0 equiv of bismuth chloride, and different functional groups can be compatible under the conditions. The related (3,4-dihydronaphthalen-2-yl) (trifluoromethyl)sulfane and 3-((trifluoromethyl)thio)-1,2-dihydroquinoline can be generated as well. Preliminary mechanistic studies reveal that the presence of bismuth chloride would promote the formation of ‘CF3S+’, which would then activate the triple bond of substrate, thus facilitating the intramolecular electrophilic 6-endo cyclization.

Hg/Pt-catalyzed conversion of bromo alkynamines/alkynols to saturated and unsaturated γ-butyrolactams/lactones via intramolecular electrophilic cyclization.

Convenient and general Hg(ii)/Pt(iv) catalyzed syntheses of γ-butyrolactams and α,β-unsaturated γ-butyrolactones/lactams are described via intramolecular electrophilic cyclizations of bromoalkynes with tosylamino and hydroxyl tethers. The reaction features the use of wet solvents, the exclusion of any base and additive, mild conditions and practical yields. We also synthesised few chiral lactams through this pathway. Additionally, it is shown that the NHTs group distanced further from the homopropargylic position assists regioselective bromoalkyne hydration to yield useful α-bromoketones. Furthermore, Boc protected bromo homo propargyl amines undergo 6-endo-dig cyclization through Boc oxygen to give bromomethylene substituted oxazinones.

Heterocyclization of amides of alkenylcarboxylic acids

The latest published data on heterocyclization of amides of alkenylcarboxylic acids have been systematized. It has been proven that the electrophilic intramolecular cyclization reaction of functionally substituted olefins opened in the 70s of the last century is a convenient way of constructing different oxygen-, nitrogen- and sulfurcontaining heterocyclic compounds. It has been noted that anilides of unsaturated carboxylic acids as bifunctional nucleophilic systems containing alkenyl and aminocarbonyl functions are useful models to study the electrophilic cyclization reaction, which leads to formation of O- and N-containing heterocycles (lactones and lactams). The last of them belong to the important types of compounds used as key blocks in the synthesis of biologically ctive alkaloids and their analogues, pharmaceutical and agrochemical products. The effective approaches to the synthesis of new types of functionalized lactones and lactams have been developed; amides of 3-butenoic, 4-pentenoic and 5-hexenoic acids are often used as substrates for their design. Along with classical methods of synthesis of lactones and lactams the literary sources relating to the use of original catalytic electrophilic systems (Nolan, Grubbs, Hoveyda), the metathesis reaction and radical processes in regio- and stereoselective cyclization of amides under mild conditions have been analyzed and summarized in the article. The synthetic versions considered are general in nature and allow to perform the targeted functionalization of O-, N-, S-containing heterocyclic small and medium-sized systems along with the cyclization processes.

Electrophilic intramolecular cyclization of functional dervatives of unsaturated compounds: VII. Synthesis of 5-arylsulfanyl-6-phenylpiperidin-2-ones in the absence of salt additives and their selective reduction and oxidation

Cinnamylacetamides reacted with arylsulfenyl chlorides in chloroform in the absence of LiClO4 affording 5-(arylsulfanyl)-6-phenylpiperidin-2-ones. Their reduction with a system LiAlH4-AlCl3 resulted in 3-(tolylsulfanyl)-1,2-diphenylpiperidine, and with Raney nickel, in 1-aryl-6-phenylpiperidin-2-ones. The latter treated with LiAlH4-AlCl3 were converted into 1-aryl-2-phenyl-piperidines. The oxidation of 5-(arylsulfanyl)-6-phenylpiperidin-2-ones with hydrogen peroxide in acetone led to the formation of 5-sulfinyl-, and with oxone, to 5-sulfonyl derivatives.

Electrophilic intramolecular cyclization of functional derivatives of unsaturated compounds: VI. Reaction of 2-(cyclohex-2-en-1-yl)acetanilides with arylsulfanyl chlorides. Structural and quantum chemical study of isomerization of 2-(2-arylsulfanyl-3-chlorocyclohexyl)acetanilides

2-(Cyclohex-2-en-1-yl)acetanilides react with arylsulfanyl chlorides in chloroform to give 2-(2-arylsulfanyl-3-chlorocyclohexyl)acetanilides which undergo isomerization into 2-chloro-3-arylsulfanylsubstituted derivatives in polar solvents. According to the results of quantum chemical calculations, the addition of arylsulfanyl chlorides to 2-(cyclohex-2-en-1-yl)acetanilides is characterized by negative Gibbs energy. Specific conformation of the isomerization products is stabilized by weak (non-covalent) interactions which make them more energetically favorable than the initial compounds. The reactions of 2-(cyclohex-2-en-1-yl)acetanilides with arylsulfanyl chlorides in nitromethane in the presence of lithium perchlorate lead to the formation of mixtures of the corresponding addition products and electrophilic intramolecular cyclization products, N-[7-(arylsulfanyl)octahydro-1-benzofuran-2-ylidene]anilinium perchlorates, which are converted into free bases by treatment with sodium ethoxide.

Cu–benzotriazole-catalyzed electrophilic cyclization of N-arylimines: a methodical tandem approach to O-protected-4hydroxyquinazolines-

A remarkably efficient approach to O-protected-4-hydroxyquinazolines has been developed via the copper–benzotriazole (Cu–BtH)-catalyzed intramolecular electrophilic cyclization of N-arylimines, achieved through the reaction of 2-aminobenzonitriles and various aldehydes.

Synthesis of novel benzopyrano[3,2-c]coumarins via tandem base promoted nucleophilic substitution and intramolecular electrophilic aromatic cyclization

Efficient and facile synthesis of 7H-benzopyrano[3,2-c]coumarins has been achieved by mild base promoted reaction of 4-chloro-3-formylcoumarin with diversely functionalized resorcinols. All the products were obtained as pure precipitates from the reaction mixture and the structure of the product was confirmed by X-ray analysis.

ChemInform Abstract: Electrophilic Intramolecular Cyclization of Functional Derivatives of Unsaturated Compounds. Part 4. Cyclosulfenylation of 5‐Hexenoic Acid Amides and Nucleophilic Cleavage of Reaction Products.

AbstractCompounds (I) react with arylsulfenyl chlorides (II) to give products of electrophilic cyclization (III).

ChemInform Abstract: Electrophilic Intramolecular Cyclization of Functional Derivatives of Unsaturated Compounds. Part 5. Cyclization of Anilides of Styrylacetic Acids in Polyphosphoric Acid.

ChemInformVolume 45, Issue 7 Preparative Organic Chemistry ChemInform Abstract: Electrophilic Intramolecular Cyclization of Functional Derivatives of Unsaturated Compounds. Part 5. Cyclization of Anilides of Styrylacetic Acids in Polyphosphoric Acid. R. I. Vas'kevich, R. I. Vas'kevich Inst. Org. Chem., Natl. Acad. Sci. Ukr., Kiev 02094, UkraineSearch for more papers by this authorA. I. Vas'kevich, A. I. Vas'kevich Inst. Org. Chem., Natl. Acad. Sci. Ukr., Kiev 02094, UkraineSearch for more papers by this authorI. Yu. Daniluk, I. Yu. Daniluk Inst. Org. Chem., Natl. Acad. Sci. Ukr., Kiev 02094, UkraineSearch for more papers by this authorM. V. Vovk, M. V. Vovk Inst. Org. Chem., Natl. Acad. Sci. Ukr., Kiev 02094, UkraineSearch for more papers by this author R. I. Vas'kevich, R. I. Vas'kevich Inst. Org. Chem., Natl. Acad. Sci. Ukr., Kiev 02094, UkraineSearch for more papers by this authorA. I. Vas'kevich, A. I. Vas'kevich Inst. Org. Chem., Natl. Acad. Sci. Ukr., Kiev 02094, UkraineSearch for more papers by this authorI. Yu. Daniluk, I. Yu. Daniluk Inst. Org. Chem., Natl. Acad. Sci. Ukr., Kiev 02094, UkraineSearch for more papers by this authorM. V. Vovk, M. V. Vovk Inst. Org. Chem., Natl. Acad. Sci. Ukr., Kiev 02094, UkraineSearch for more papers by this author First published: 31 January 2014 https://doi.org/10.1002/chin.201407026Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume45, Issue7February 18, 2014 RelatedInformation

A facile and efficient synthesis of functionalized 4-oxo-2-(phenylimino)thiazolidin-5-ylideneacetate derivatives via a CuFe2O4 magnetic nanoparticles catalyzed regioselective pathway

Nano-CuFe2O4 spinel has been found to exhibit strong catalytic activity in the cascade reaction involving 1,4-addition and intramolecular electrophilic cyclization in a perfectly regiocontrolled manner and a series of functionalized 4-oxo-2-(phenylimino)thiazolidin-5-ylideneacetate derivatives were generated successfully.

Electrophilic intramolecular cyclization of functional derivatives of unsaturated compounds: IV. Cyclosulfenylation of 5-hexenoic acid amides and nucleophilic cleavage of reaction products

Anilides of 5-hexenoic acid react with arylsulfenyl chlorides in nitromethane in the presence of lithium perchlorate affording products of electrophilic cyclization, N-{6-[(arylsulfanyl)methyl]tetrahydro-2H-pyran-2-ylidene}anilinium perchlorates. The treatment of the latter with sodium acetate or secondary cycloalkylamines in the presence of water results in the opening of the tetrahydropyran ring and provides anilides or cycloalkylamides of 6-arylsulfanyl-5-hydroxyhexanoic acid.

Electrophilic intramolecular cyclization of functional derivatives of unsaturated compounds: V. Cyclization of anilides of styrylacetic acids in polyphosphoric acid

Anilides of styrylacetic acids at heating in polyphosphoric acid undergo an intramolecular cyclization giving 1,5-diarylpyrrolidin-2-ones, 5-aryl-1,3,4,5-tetrahydro-2H-benzazepin-2-ones, and 5-(3-fluorophenyl) dihydrofuran-2(3H)-one, where the ratio of the products depends on the character of the aromatic substituents in the amide and styrene fragments of the substrate.

ICl‐Induced Intramolecular Electrophilic Cyclization of 1‐[4′‐Methoxy(1,1′‐biphenyl)2‐yl]alkynones—A Facile Approach to Spiroconjugated Molecules

Spiro compounds: An iodine monochloride-induced intramolecular cyclization of 1-[4'-methoxy(1,1'-biphenyl)2-yl]alkynones has been developed (see scheme). An electrophilic iodocyclization selectively takes place at the ipso position (versus the ortho electrophilic aromatic substitution) to afford 4'H-spiro(cyclohexa[2,5]diene-1,1'-naphthalene)-4,4'-diones, a new group of spiroconjugated compounds.

ChemInform Abstract: Synthesis of 7‐Iodo(arylsulfanyl)methyl‐7,8‐dihydro[1,3]thiazolo[2,3‐i]purinium Pentaiodide (Perchlorates) and Their Transformation into 4‐Amino‐5‐(1,3‐thiazol‐2‐yl)imidazole Derivatives.

AbstractThe intramolecular electrophilic cyclization of 6‐allylsulfanylpurine (I) with iodine and arenesulfenyl chlorides, respectively and the subsequent behavior of the resulting fused heterocycles toward nucleophiles is explored.

ChemInform Abstract: Intramolecular Electrophilic Cyclization of Functional Derivatives of Unsaturated Compounds. Part 3. Reaction of N,4‐Diarylbut‐3‐enamides with Arenesulfenyl Chlorides. Synthesis of 5‐Aryl‐4‐arylsulfanyl‐2,3,4,5‐tetrahydro‐1H‐1‐benzazepin‐2‐ones.

AbstractThe reaction of N,4‐diarylbut‐3‐enamides (I), (IV), and (VI) with arenesulfenyl chlorides (II) is studied and the different underlaying mechanisms are discussed.

Synthesis of 7-iodo(arylsulfanyl)methyl-7,8-dihydro-[1,3]thiazolo[2,3-i]purinium pentaiodide (perchlorates) and their transformation into 4-amino-5-(1,3-thiazol-2-yl)imidazole derivatives

Intramolecular electrophilic cyclization of 6-allylsulfanylpurine by the action of iodine and arenesulfenyl chlorides gave 7-iodomethyl-7,8-dihydro[1,3]thiazolo[2,3-i]purin-6-ium pentaiodide and 7-arylsulfanylmethyl-7,8-dihydro[1,3]thiazolo[2,3-i]purin-6-ium perchlorates, respectively. 7-Iodomethyl-7,8-dihydro-[1,3]thiazolo[2,3-i]purin-6-ium iodide reacted with sodium and potassium alkoxides to produce alkyl N-[5-(4-methyl-1,3-thiazol-2-yl)-1H-imidazol-4-yl]formimidates, and its reaction with secondary cyclic amines afforded 5-(4-methyl-1,3-thiazol-2-yl)-N-[morpholin-4-yl(or piperidin-1-yl)methylidene]-1H-imidazol-4-amines. Successive treatment of 7-arylsulfanylmethyl-7,8-dihydro[1,3]thiazolo[2,3-i]purin-6-ium perchlorates with sodium acetate and morpholine led to the formation of 5-(4-arylsulfanylmethyl-4,5-dihydro-1,3-thiazol-2-yl)-N-(morpholin-4-ylmethylidene)-1H-imidazol-4-amines.

Iodine-Mediated Intramolecular Electrophilic Aromatic Cyclization in Allylamines: A General Route to Synthesis of Quinolines, Pyrazolo[4,3-b]pyridines, and Thieno[3,2-b]pyridines

An unprecedented synthesis of aromatic ring annulated pyridines from suitably substituted primary allylamines via intramolecular electrophilic aromatic cyclization mediated by molecular iodine under mild conditions is described.

Intramolecular electrophilic cyclization of functional derivatives of unsaturated compounds: III. Reaction of N,4-Diarylbut-3-enamides with arenesulfenyl chlorides. Synthesis of 5-aryl-4-arylsulfanyl-2,3,4,5-tetrahydro-1H-1-benzazepin-2-ones

N-Aryl-4-phenylbut-3-enamides reacted with arenesulfenyl chlorides in chloroform to give N,4-diaryl-3-arylsulfanyl-4-chlorobutanamides, whereas in acetic acid in the presence of lithium perchlorate N-[4-arylsulfanyl-5-phenyltetrahydrofuran-2-ylidene]arenaminium perchlorates were obtained. Reactions of arenesulfenyl chlorides with N,4-diarylbut-3-enamides having strong electron-donating groups in positions 3 and 4 of the N-aryl substituent afforded 5-aryl-4-arylsulfanyl-2,3,4,5-tetrahydro-1H-1-benzazepin-2-ones.

ChemInform Abstract: Intramolecular Electrophilic Cyclization of Functional Derivatives of Unsaturated Compounds. Part 2. Synthesis and Transformation of N‐{(2Z)‐5‐ [(Arylsulfanyl)methyl]dihydrofuran‐2(3H)‐ylidene}‐N‐alkyl(aryl)aminium Perchlorates.

AbstractThe cyclization of amides (I) with arylsulfenyl chlorides (II) in the presence of LiClO4 gives rise to perchlorates (III), which are used as starting compounds in the synthesis of lactones (V), amides (VII), and sulfones (VIII).